The present invention relates to a cassette type magnetic recording and reproducing apparatus and to an adapter for enabling mounting and using two kinds of cassettes of large and small sizes in a same cassette receiving portion.
Besides the generally used compact cassettes, there is often used a very small microcassette (trade name) which is smaller than the compact cassette, or an L-cassette (trade name) which is larger than the compact cassette, the size of the cassette utilized varying in accordance with demand.
However, these large and small cassettes require respective recording and reproducing apparatus owing to their different structures, and it is impossible to use a single apparatus for two kinds of different cassettes without an adapter. Therefore, as disclosed in Japanese Utility Model Application Publication No. 22,573/72, in order to use a small type cassette in an apparatus for a large type cassette, a hub gap of the small type cassette and the inserting window portion of a head and pinch roller are made as large as in the large type cassette but small in external appearance.
With the above construction, two large and small cassettes are alternately usable in a single tape recorder, but since the small type cassette cannot be made too small as compared with the large type cassette the hub gap will be wide and the space between the outer wall will be narrow to provide for exchangeability, and as a result, a long tape cannot be wound and useless space is required.
Further, in Japanese Patent Laid-open No. 88,503/74 filed by the same applicant or Japanese Patent Laid-open No. 84,617/73, two kinds of large and small cassettes are used in one and the same magnetic recording and reproducing apparatus, so that an adapter for the small cassette is formed in compliance with the shape of the large type cassette. However, these adapters must have their own separate head, pinch roller and the like, and when such adapter is used, a cassette lid of the apparatus cannot be closed and the tape recorder becomes inconvenient for handling.